1. Field
The present invention relates to wireless communication and more particularly, an apparatus and a method for coordinating in-device coexistence interference based on time division multiplexing (TDM) scheme in a wireless communication system.
2. Background
A conventional wireless communication system exploits a single frequency band for data transmission. For example, the second-generation wireless communication system uses bandwidth of 200 KHz to 1.25 MHz while the third-generation wireless communication system uses bandwidth of 5 MHz to 10 MHz. To meet the demand for ever-increasing transmission capacity, the recent 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) or IEEE 802.16m is expanding the bandwidth up to 20 MHz or more. Although it is essential to increase bandwidth to meet the demand for high transmission capacity, supporting high bandwidth even when quality of service required is low may incur large power consumption.
In this respect, multiple component carrier systems are now emerging, which define a carrier wave to use a predetermined frequency band and center frequency and support broadband data transmission and/or reception through a plurality of carrier waves. Both narrow and broadband data communication are supported by utilizing one or more carrier waves. For example, if a carrier wave corresponds to the bandwidth of 5 MHz, a maximum bandwidth of 20 MHz can be supported by using four carrier waves.
Due to ubiquitous access networks today, users at different places are able to connect to networks different from each other and continuously maintain connectivity to the networks wherever they may be. In a conventional use case where a UE is allowed to communicate with only a single network system, the user has to carry different types of devices supporting the respective systems. As functions implemented in a single UE are advanced and diversified these days, however, even a single UE can perform communication with multiple network systems simultaneously and user's convenience is greatly enhanced.
However, in case a single UE performs communication simultaneously through frequency bands of a plurality of network systems, in-device coexistence interference may occur. In-device coexistence interference refers to such kind of interference that causes interference caused by data transmission in a particular frequency band on another frequency band. For example, in case a single UE supports the Bluetooth and LTE (Long Term Evolution) system together, the in-device coexistence interference may be developed between the frequency bands of the Bluetooth and the LTE system. The in-device coexistence interference is usually generated when separation between boundaries of frequency bands in a heterogeneous network system is not wide enough.
Frequency division multiplexing (FDM) and time division multiplexing (TDM) may be used as the technique to avoid in-device coexistence interference. The FDM technique controls in-device coexistence interference developed between a first frequency band of a first network system and a second frequency band of a second network system by shifting the frequency band of either of the network systems. On the other hand, the TDM technique controls the in-device coexistence interference by separating transmission time of the first network system from reception time of the second network system. However, there still needs an agreement about a specific operating procedure between a UE and an eNB for controlling in-device coexistence interference.